1. Field of the Invention
The present invention relates generally to a power socket with a switch for enabling power supply to the socket. More specifically, the present invention is related to a power socket that can be enabled using switches that are isolated from socket power, and actuated by some type of user intervention.
2. Description of the Related Prior Art
Power sockets that provide activation/de-activation switching of the power supplied to the socket are known in the art. For example, switched sockets are known that activate/de-activate a power socket based on safety criteria. U.S. Pat. No. 5,865,635 to Hsiang et al. is representative of this type of socket, in which power is supplied to the socket only upon insertion of a mating connector plug. The prongs of the mating connector plug activate contacts within the socket that provide power to the various legs of the plug prongs inserted into the power socket. Each prong of the inserted mating plug activates a contact which enables power to another prong of the mating connector socket. This arrangement provides a safety feature, whereby an object inserted into one of the socket receptacles will not cause that receptacle to be powered, thereby reducing the possibility of electric shock.
Other known socket configurations include that represented by U.S. Pat. No. 5,374,199 to Chung, in which a power socket is activated only upon activation of a plunger type mechanism, which closes contacts within a socket to provide power to the inserted prongs of the mating connector plug. This feature provides a safety and security feature, because the socket remains unpowered until an appropriately configured mating connector plug is inserted into the socket.
Similarly, U.S. Pat. No. 5,984,700 to Chang discloses a socket which remains unpowered until a mating connected plug is fully inserted and rotated 90 degrees. The mating connector plug only receives power once it has been inserted into the socket and rotated 90 degrees, upon which contacts within the socket are closed to provide power to the various socket terminals. In addition, once the mating connector plug is inserted and rotated 90 degrees in the socket, the mating connector plug is secured within the socket, thereby providing a feature which prevents the unintentional disconnection of the socket and plug once power is being supplied.
U.S. Pat. No. 3,781,495 to Splingaerd shows a socket provided with an access cover, which disconnects power to the socket once it is pivoted away from the socket receptacle. The pivoted socket cover interrupts power to at least one leg of the connector socket, which interrupts the power supply to the mating connector plug. In addition, since the socket cover prevents access to the socket unless it is pivoted open, the cover acts as a safety shut-off, useful for devices drawing power from the socket, in addition to preventing potential harm to an individual accessing the socket.
In all of the above disclosures, the actuating switches that provide power to the socket receptacles also carry socket power. That is, the switching elements are typically contacts which conduct power to a particular terminal of the socket once actuated. The devices of the prior art typically do not disable power to a socket completely, nor do they control switching of the power source that provides power to the socket. Moreover, the prior art does not show any way of determining whether the socket is powered based on simple visual observation.
The present invention overcomes the drawbacks of the prior art by providing a switched power socket in which the switching signal can be isolated from socket power. The present invention further provides an indication of whether the socket is powered. Furthermore, the present invention provides several safety features which help to ensure safe and proper operation of the socket.
An example of a power socket in which the enabling socket switch is electrically isolated from the output of the power source to the socket is shown in U.S. Pat. No. 6,495,775, assigned to the assignee of this application. The present invention is an improvement on the device of this latter patent.